Figure 2.

Nuclear-mitochondrial conflict in the bladder campion Silene vulgaris. Populations of gynodiecious plants such as S. vulgaris consist of females (pictured here) and hermaphrodites, the latter producing both seeds
and pollen [24,26]. Females are produced from hermaphrodites by mitochondrial variants that interfere
with the development of the stamens, called cytoplasmic male sterility (CMS). Because
they are primarily transmitted through ovules but not pollen, the mitochondria gain
a fitness advantage from reducing allocation to male reproduction. CMS variants, however,
are often subject to counter-evolutionary changes in nuclear-encoded genes that suppress
their effects and restore male fertility. Photo courtesy of Doug Taylor, University
of Virginia.